Which statement accurately synthesizes how insulin and glucagon have opposing effects across tissues to maintain blood glucose homeostasis?

• A. Insulin acts primarily on muscle, liver, and adipose to promote glucose uptake and storage (glycogenesis, lipogenesis), whereas glucagon acts mainly on liver (and indirectly on adipose) to promote glycogen breakdown, gluconeogenesis, and lipolysis; together they balance postprandial and fasting states.
• B. Glucagon only affects muscle metabolism by increasing muscle glycogen synthesis, while insulin only affects the liver by stimulating gluconeogenesis; hence they don't directly oppose each other.
• C. Insulin and glucagon both act only on adipose tissue but use different receptor subtypes: insulin breaks down triglycerides and glucagon synthesizes them; both therefore lower blood glucose.
• D. Insulin's main role is to raise blood glucose during fasting by promoting hepatic gluconeogenesis, while glucagon lowers blood glucose after meals by stimulating muscle uptake, making their effects complementary rather than opposing.

Answer: (A)